Times of arrival (TOA) of signals in the Kerr-MOG black hole

Abstract

Modified gravity (MOG) theories are alternatives to general relativity (GR) that arose primarily from the need to explain the observed galactic flat rotation curves without invoking the elusive dark matter hypothesized by GR. A well known MOG is the Scalar-Tensor-Vector-Gravity (STVG) developed by Moffat, who has also found a spinning solution called the Kerr-MOG black hole (BH) characterized by the spin $a$ and MOG parameter $\alpha$, the latter determining the strength of the gravitational vector forces. We consider the static-MOG metric ($a=0$) to first understand how the nature of geometry drastically changes depending on different sectors of $\alpha$. Then we study the influence of $\alpha$ in each sector on a new astrophysical diagnostic caused by \textit{frame dragging}, viz., the difference $\Delta t$ in the times of arrival (TOA) at the observer of signals emanating from a variable pulsar (PSR) passing behind a Kerr-MOG lens in a PSR-BH binary system. The study generalizes the zeroth order Laguna-Wolszczan formula up to third PPN order in $\left(1/r\right)$ using thin-lens approximation, which reveals how $\Delta t$ is influenced both by $a$ and $\alpha$. The magnitude and sign of $\alpha$ indicate deviations from GR ($\alpha =0$) and future measurements may constrain $\alpha$ provided a suitable binary is identified.

arXiv comment17 pages, 1 figure

References in corpus (38)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Discovery of a Supernova Explosion at Half the Age of the Universe and its Cosmological Implications
• Modified f(R) gravity consistent with realistic cosmology: from matter dominated epoch to dark energy universe
• Gravitational lensing in the strong field limit
• Scalar-Tensor-Vector Gravity Theory
• Black holes on the brane
• Search for Low-Mass WIMPs with SuperCDMS
• Galaxy Rotation Curves Without Non-Baryonic Dark Matter
• Mapping spacetimes with LISA: inspiral of a test-body in a `quasi-Kerr' field
• The Extreme Spin of the Black Hole in Cygnus X-1
• Black Holes in Modified Gravity (MOG)
• Gravity, Stability and Energy Conservation on the Randall-Sundrum Brane-World
• The MOG weak field approximation and observational test of galaxy rotation curves
• A test of general relativity from the three-dimensional orbital geometry of a binary pulsar
• Incidences between points and lines on a two-dimensional variety
• Impact of a global quadratic potential on galactic rotation curves
• Modified Gravity Black Holes and their Observable Shadows
• The Bullet Cluster 1E0657-558 evidence shows Modified Gravity in the absence of Dark Matter
• Probing the Spacetime Around Sgr A* with Radio Pulsars
• The MOG Weak Field approximation II. Observational test of Chandra X-ray Clusters
• Galaxy Cluster Masses Without Non-Baryonic Dark Matter
• Rotational Velocity Curves in the Milky Way as a Test of Modified Gravity
• Testing modified gravity with globular cluster velocity dispersions
• Formalism for testing theories of gravity using lensing by compact objects. II: Probing Post-Post-Newtonian metrics
• Measuring spin of a supermassive black hole at the Galactic centre -- Implications for a unique spin
• Accretion disks around black holes in Scalar-Tensor-Vector Gravity
• Pulsar-Black Hole Binaries in the Galactic Center
• Modified gravity black hole lensing observables in weak and strong field of gravity
• Features of galactic halo in a brane world model and observational constraints
• Cosmological observations in a modified theory of gravity (MOG)
• Neutron stars in Scalar-Tensor-Vector Gravity
• Pulse Arrival-Times from Binary Pulsars with Rotating Black Hole Companions
• How is Binary Radio-Pulsars with Black Holes Population Rich?
• String effect on the relative time delay in the Kerr-Sen black hole
• Gravitational time advancement and its possible detection
• Comment on "Impact of a Global Quadratic Potential on Galactic Rotation Curves"
• Influences of Dark Energy and dark matter on Gravitational Time Advancement
• Terrestrial Sagnac delay constraining modified gravity models

Cited by in corpus (3)

• Gravitational synchrotron radiation and Penrose process in STVG theory
• Terrestrial Sagnac delay in scalar-tensor-vector-gravity
• Can a regular black hole be observationally distinguished from singular black holes as spinning lens partner in PSR-BH binaries?